1. Field of the Invention
The present invention relates to a low temperature physical distribution system, specifically a low temperature physical distribution system having a purchase and sale system aside from the distribution system for handling perishable foods including hauled fishes of which storage management is absolutely necessary when keeping the objects to be distributed in storage for maintaining the quality thereof, and a method and an apparatus for maintaining the quality thereof in an auction market of marine products.
2. Description of the Related Art
There are two types of systems of distributing perishable foods including hauled fishes, i.e., a conventional distribution system in which merchandise are gathered in a market and traders trade while ascertaining the quality according to their experiences and five senses; and a distribution system utilizing information technology, wherein the trade is done in a virtual market, that is, the low temperature distribution system is separated from the purchase and sale system.
In the case of a distribution system where the trade is completed on a ship and the distribution target place is already determined when hauled fishes are landed, there is no problem as the temporary storage thereof is not necessary. However, in both systems mentioned above, problems have been indicated concerning the temporary storage at the step of trade in the market, and improvements have been proposed.
In Japanese Unexamined Patent Publication No.2000-14315 is disclosed an apparatus and method of displaying and storing hauled fishes in storage capable of hygienic storage aiming to solve the problems which arise from the sale at auction on floor concerning hygiene and quality of the hauled fishes.
Namely, a display and storage apparatus which is composed of a cooling section having a brine passage provided inside a cooling plate capable of displaying hauled fishes on the surface thereof and a thermal insulation section provided at the bottom of the cooling section, a brine for food use being supplied to the brine passage, is provided in a fish market, and the distribution process of hauled fishes is done on the display and storage apparatus.
Said display and storage apparatus is surrounded by an enclosure wall of appropriate height to keep the temperature of the hauled fishes at a uniform temperature by preventing the diffusion of cold air. It is claimed that the whole temperature of the hauled fishes is maintained stable and uniform by properly adjusting the height of the surrounding wall and the quantity of air introduction in accordance with the condition and state of display of the hauled fishes.
This proposal is satisfying in regard to temperature control, however, much time and effort are needed to replace the hauled fishes onto the cooling plate, as the cooling plate is fixed on the floor. Besides, no concrete mention is made of the construction of the surrounding wall.
Moreover, as no control means for humidity control of the low temperature region, the space for displaying the hauled fishes is provided, the problem of deterioration in quality due to transfer of water from the surface of the hauled fishes and drying thereof arises.
In Japanese Unexamined Patent Publication No.2000-201618 is proposed an improvement of a drainboard for placing fish thereon used in a sale at auction of tuna fish. The proposal is intended to provide a hygienic, durable, and lightweight drainboard which, at the same time, is improved in the easiness in handling with a hook and does not damage the skin or body of the fish when tuna fish is placed on or removed from the drainboard. Aluminum is used for the material of the plates and crosspieces composing the drainboard, and a sloped face is formed along the side of the plate in full length to prevent the damage of the skin of the fish.
Comparatively simple apparatuses such as the hook and the drainboard are used in a fish market, as cited in the disclosure.
This is because there is a characteristics situation of a fish market that the fish market has a public function to cope with emergency cases in addition to its proper function.
It is assumed that the market is used for disaster relief using ships and as an emergency shelter for people, as it is located adjacent to a wharf. Therefore, an equipment which would become obstacle in such an emergency is not allowed to be installed or placed in the market other than when it is used as an auction market. The equipment for trading is demanded to be installed and removed speedily. The fact that equipment of which the installation requires much expense of time and effort is not accepted and hooks and drainboards are used conveniently is thought to be due to the circumstance mentioned above.
When handling frozen tuna fish, condensation of moisture in the surrounding air on the surface of the fish or frosting occurs. The condensation heat or heat of solidification due to the phase-change of water effects thawing of the frozen fish, which causes the problem that the skin of the fish is damaged and in its turn the quality is deteriorated.
Therefore, the control of humidity of the surrounding air of hauled fishes is also an important factor for maintaining quality.
Recently, a greater number of distribution systems have become separated from a purchase and sale system owing to the development of information technology. So, a purchase and sale system based on objective data such as, in the case of hauled fishes, production region, name of fishing boat, history of storage temperature, analysis data of freshness and so on has become increasingly adopted instead of a system in which traders trade based on their experience and mutual reliance while observing the products of trade closely and ascertaining the quality of them.
It is probable that the products of trade landed on a market in Okinawa can be traded in a market in Hokkaido. Therefore, in a system requiring temperature control, more severe temperature control and disclosure of data have become necessary.
By the way, the quality change due to microorganisms is the cause which induces problems the most frequently among the causes of the deterioration of food quality. Microorganisms such as bacteria, mold, and yeast cause the quality change.
Among them, enteritis Vibrio is the one on which prime importance is put as food poisoning microbe in Japan. This microbe is comparatively weak in low temperature, its growth is suppressed at temperatures below 5xc2x0 C., and its multiplication is impossible at temperatures below 10xc2x0 C. However, enteritis Vibrio can live in seawater and attaches to the body surface or gill of fish and shellfish.
A sanitation management system according to HACCP which is composed mainly of Hazard Analysis (HA) and Critical Control Point (CCP) has been introduced for the establishment of measures against deterioration of food. From the point of view of said HACCP, the first step for the prevention of the deterioration in quality of marine products is also to maintain the quality thereof in the auction market which is the first channel of trade. Therefore, establishment of preferable sanitation management method based on the prevention of multiplication of harmful microorganisms including said enteritis Vibrio and the equipment for maintaining the quality of hauled fishes, the objects of auction, are strongly demanded.
The present invention was made in the light of the problems mentioned above. The object of the invention is to provide low temperature zone forming equipment having a storage function capable of effective control of temperature and humidity and a method and equipment for maintaining the quality of hauled fishes in an auction market of marine products such as fishes, shellfishes, for constituting a low temperature distribution system closely linked with a purchase and sale system in consideration of the characteristics of the market.
The low temperature distribution system according to the present invention is characterized in that, in a low temperature distribution system having a separate purchase and sale system, low temperature zone forming equipment for keeping in storage the object to be distributed has a temperature and humidity censer and a control means for sending the data detected with the censers to a purchase and sale system.
As cited above, the invention is low temperature forming equipment in a low temperature distribution system which has a separate purchase and sale system and in which the temperature of merchandise is controlled in the flow thereof from production to consumption.
For example, the landed and auctioned hauled fishes before shipment are temporarily kept in storage under controlled temperature and humidity by use of temperature and humidity censers in the space surrounded with the enclosure wall. The system is provided with a data transmission control means to certify to buyers in remote districts the storage condition data of the fishes displayed under a proper low temperature and humidity controlled. The temperature may be indicated on the enclosure wall and the picture may be distributed to markets in remote districts. When buyers are on the same place, the temperature may be display only on the wall.
It is preferable that said low temperature zone forming equipment has a means for forming a low temperature zone of controlled humidity around the objects to be kept in storage, the means having a cooler, humidity controlling means, and air flow forming apparatus.
The low temperature forming equipment according to the present invention has a humidity controlling function other than that of controlling temperature in its storage function in addition to the means to send said storage condition data to the buyers in remote districts. The equipment is provided with a temperature control means having a cooler and a humidity control means having a humidity controller referred to later, by which the chilled air of predetermined temperature and relative humidity is obtained. Further, a low temperature zone of controlled humidity is formed around the objects to be kept in storage by the use of a blower or agitator.
Accordingly, the objects to be kept in storage are kept in a low temperature state and the transfer of moisture between the surface of the objects and the low temperature zone is prevented.
As a result, in the case of not-frozen foodstuff the transfer of moisture to the ambient air from the surface of the foodstuff and drying thereof is prevented, in the case of frozen fishes such as frozen tuna the condensation of moisture or frosting on the surface thereof, or thawing in its turn is prevented, and the quality is maintained.
It is preferable that said humidity control means has a dehumidifier for preventing dew-condensation or frosting due to phase-change for the frozen objects to be kept in storage, and a humidifier for increasing the dew-point temperature in the zone above the surface temperature of the object to prevent the transfer of moisture between the surface of the object and the ambient air of not-frozen, perishable foods, the objects to be kept in storage.
Thus, in the case the object to be kept in storage is a frozen fish such as tuna, the relative humidity of the low temperature zone surrounding the object is decreased to prevent the transfer of moisture by controlling humidity, and in the case the object to be kept in storage is a not-frozen, perishable foodstuff, the humidity of the low temperature zone surrounding the object is controlled so that the dew-point temperature is higher than the surface temperature of the object, for when said dew-point temperature is lower than that of the surface of the object, the transferring of the moisture from the surface of the object to the low temperature zone occurs, and the value as merchandise is damaged due to the drying of the surface thereof.
It is preferable that said low temperature zone forming equipment is composed of a chilled air generator comprising a cooler with a blower and an enclosure wall composed of a flexible, hollow structure surrounding the objects to be kept in storage, said enclosure wall having ports for entrance and exit of water, a connection port for supplying the chilled air from the chilled air generator at an end part thereof, and exhaust openings formed of knitted cloth along the inside face of the enclosure wall.
The invention cited above is an example of the structure of the low temperature zone forming equipment. The folded enclosure wall is inflated by blowing air thereinto. The wall is brought to intimate contact with the part of the floor formed into an anchor part. The chilled air produced by the chilled air generator located outside the enclosure wall is supplied to the inflated enclosure wall which itself functions as a duct, and the chilled air flows through the hollow space in the inflated wall and exhausted from exhaust openings formed of knitted cloth provided on the inner side face of the enclosure wall to the ambient space of the objects kept in storage within the enclosure to form the low temperature zone within the enclosure.
It is preferable that said low temperature zone forming equipment is composed of a chilled air generator comprising a cooler with a blower and a panel type enclosure wall surrounding the objects to be kept in storage, and a cross-duct connected to said chilled air generator is provided within the enclosure.
The invention cited above is another example of embodiment of the low temperature zone forming equipment.
Said chilled air generator is preferable to have a humidity controller.
In the low temperature zone forming equipment composed of said chilled air generator and enclosure wall, a humidity controller is attached to the chilled air generator to increase or decrease the humidity of the chilled air blown off into the enclosure. Thus the humidity in addition to the temperature of the low temperature zone is controlled to prevent the transfer of moisture between the surface of the object to be kept in storage and the air in the low temperature zone.
Said low temperature zone forming equipment may be composed of a cooler embedded in the floor, an enclosure wall for enclosing the objects to be kept in storage in the space occupied with the chilled air produced by said cooler, and an agitator for forming air flow by agitating the chilled air in the enclosed space.
The low temperature zone forming equipment cited above is a preferable structure of the type other than the types, each being composed of an enclosure wall and chilled air generator as described in the foregoing. In the equipment, a cooling part is placed under the surface of the floor of the low temperature zone, objects to be kept in storage are placed in the chilled air cooled by the cooling part and enclosed with an enclosure wall, and the chilled air within the enclosure is agitated by an agitator to form a low temperature zone of uniform temperature capable of being controlled.
It is preferable that a humidity controller is provided inside the enclosure; the humidity of the low temperature zone is decreased for the objects to be kept in storage in frozen state to prevent the occurrence of dew condensation or frosting due to phase-change of moisture on the surfaces of the objects; the humidity is increased for not-frozen, perishable foods, the objects to be kept in storage, to keep the dew-point temperature of water in the low temperature zone above the surface temperature of said objects for preventing the transfer of moisture from the surfaces of the objects.
In the low temperature forming equipment composed of a cooling part placed under the surface of the floor, an enclosure wall, and an agitator provided inside the enclosure, a humidity controller is provided inside the enclosure to secure highly effective storage performance by controlling the humidity in addition to the temperature within the enclosure. In the case the objects to be kept in storage are not-frozen, perishable foodstuff, drying of the food stuff is prevented by increasing the humidity of the low temperature zone so that the dew-point temperature of water in the zone is above the surface temperature of the objects, and in the case the objects to be kept in storage are frozen foodstuff, the occurrence of dew-condensation or frosting is prevented by decreasing the humidity.
Next, a quality maintaining method in an auction market of marine products according to the present invention is characterized in that hauled fishes are placed on carrying faces maintained near freezing temperature above 0xc2x0 C., said hauled fishes are surrounded with an enclosure wall, chilled air of about 3xc2x0 C. or below is blown to said hauled fishes, and the air temperature within the enclosure is kept at about 10xc2x0 C. or below.
The invention is to perform the most suitable temperature control for the marine products just after landed in an auction market and to prevent the occurrence of severe problems in maintaining the quality afterward.
First of all, hauled fishes are placed on a cooled plate of which the surface temperature is kept near freezing temperature of water above 0xc2x0 C. in order to prevent freezing, then the hauled fishes placed on the plate is surrounded with a enclosure wall to form a space partitioned from the surrounding space. Chilled air of about 3xc2x0 C. or below is blown off into the enclosed space to produce the enclosed space of a temperature of about 10xc2x0 C. or below at which temperature the multiplication of harmful bacteria including enteritis Vibrio is prevented, and the quality of the hauled fishes are maintained.
A preferable quality maintaining equipment in an auction market of marine products employing the quality maintaining method according to the present invention is an equipment capable of maintaining quality of perishable fish and shellfish in an auction market characterized in that the equipment is composed of cooling panels to place hauled fishes thereon; an air fence consisting of a foldable enclosure wall to surround the hauled fishes placed on said panels and a chilled air blow-off section provided on said enclosure wall; air curtains to shutoff the chilled air within the enclosure; and a chilled air generator comprising a cooler and blower for producing said chilled air; a space partitioning being done by said air fence and curtains, and the air temperature inside the partitioned space being maintained at low temperature of 10xc2x0 C. or below by the chilled air of about 3xc2x0 C. blown off from said chilled air blown-off parts.
In the equipment cited above, cooled panels are provided, a foldable air fence forms an enclosed space partitioned from the surroundings for enclosing the hauled fishes placed on the cooled panels, chilled air from a chilled air generator is introduced into a chilled air blow-off section at the bottom part of the fence from a connection port at an end of the air fence and blown off from the chilled air blow-off openings formed on the inside face of the air fence, and air curtains shutting out the chilled air enables the entrance and exit of the hauled fishes and workers. Chilled air of about 3xc2x0 C.xcx9c7xc2x0 C. is introduced from the chilled air generator into the fence to maintain the temperature of the low temperature zone within the enclosure partitioned with the fence at about 10xc2x0 C. or below to prevent the multiplication of harmful bacteria including enteritis Vibrio adhering to the hauled fishes. The surface temperature of the cooled panels for placing thereon the hauled fishes to be auctioned is kept near freezing temperature above 0xc2x0 C. in order to prevent the freezing of the hauled fishes thereon.
The cooled panel of said quality maintaining equipment may preferably be provided with an embedded tube connected to a brine cooler, or composed of a tube connected to a brine cooler and formed into a mat, the temperature of the surface thereof being maintained near freezing temperature above 0xc2x0 C.
The invention cited above describes the structure of the cooled panel in the quality maintaining equipment. The cooled panel is composed of a tube embedded in the floor of the auction market or a mat having a tube integrated in the bottom part thereof or a tube formed into a mat, the tube being connected to a brine cooler operated using brine for food use to be supplied with brine of about xe2x88x922xc2x0 C. The temperature of the surface of the panel is maintained at 0xc2x0 C. or a little higher.
The air fence of said quality maintaining equipment may preferably be a temporal wall of air balloon type and provided with a chilled air blow-off section on the inside upper or lower part thereof.
The invention cited above describes the structure of the air fence in the quality maintaining equipment. Air is pumped into a flat, flexible, air-tight vessel to expand it to form an enclosure wall on the lower or upper part of which is provided a chilled air duct having a plurality of openings for blowing off the chilled air.
The cooler of said quality maintaining equipment may preferably be an air-cycle refrigerator.
In the invention cited above, the chilled air generator in said quality maintaining equipment produces low temperature air by air-cycle refrigeration in which air is compressed and the compressed high pressure, high temperature air is cooled to near ordinary temperature, then the cooled air is expanded in an expansion turbine.